GREY'S ANATOMY - "Crash Into Me -- Part One" - An ambulance crash endangers the lives of the paramedics involved, as Meredith and the Chief work on-site to save them, Bailey treats a patient who refuses her help, and Ava returns for Alex and meets his other girlfriend in the process, on "Grey's Anatomy," THURSDAY, NOVEMBER 22 (9:00-10:02 p.m., ET) on the ABC Television Network. (ABC/RON TOM) KATHERINE HEIGL, SANDRA OH, JOHN BILLINGSLEY